Association between psoriasis, psoriatic arthritis and gout: a nationwide population-based study

Background Psoriasis is a common skin disease that has been recently found to be associated with various systemic inflammatory disorders. However, the association between psoriasis and gout has not been well defined. Objective We investigated whether there is an association between psoriasis, psoriatic arthritis and gout in a large population of patients in Taiwan. Methods A nationwide population-based cross-sectional study was performed using the Taiwanese National Health Insurance Research Database (NHIRD). A total of 114 623 patients with gout and 114 623 patients without gout (1 : 1 propensity score-matched according to age, sex, income category and urbanization level) were identified. The prevalence of psoriasis, psoriatic arthritis and other comorbid diseases in these two groups of patients was compared. Adjusted odds ratios (OR) were calculated using conditional logistic regression. Results There was an increased prevalence of psoriasis in patients with gout compared with patients without gout (1.6% vs. 1.1%, P < 0.0001). Subgroup analysis showed an increased prevalence of psoriatic arthritis (0.3% vs. 0.1%, P < 0.0001) in patients with gout compared with patients without gout. In addition, multiple conditional logistic regression analysis showed that gout was significantly associated with psoriasis (adjusted OR 1.30, 95% CI 1.20-1.42) and psoriatic arthritis (adjusted OR 2.50, 95% CI 1.95-3.22). After stratification by age and sex, it was found that the strength of the association between gout and psoriasis was similar among males and females but varied according to age group, with patients aged 41-50 years having the strongest association. Conclusion Gout is significantly associated with psoriasis and psoriatic arthritis in the Taiwanese population, and the strength of the association varies with the patient's age. Further studies are warranted to elucidate the molecular mechanisms underlying this association.